Pump



March 28, 1944. BRENNAN 2,344,964

PUMP

Filed Sept. 25, 1941 INVENTOR- BY .70 SEPH B. BEE/VIVA M w A AT7OPIVEYS.

Patented Mar.-28,'1944 comm PUMP Joseph B. Brennan, Cleveland, Ohio Application September 25,1941, Serial No; 412,300 2v Claims. (oi, loc -13's) This invention relates asindicated to pumps and more particularly to the type of pump wherein a rotor provided with reciprocable vanes rotates within a bore, so formed that the vanes at opposite ends have engagement with the inner periphery of the bore for substantially all positions of the rotor.

It is a common characteristic of pumps of the general character to'which this invention relates that the bore within which the rotor is mounted has a curved surface made up of two concentric arcsoi difierent radii, such arcs being joined by means oi special curves of various forms;

Mounted in the bore is acylindrical rotor, the axis of which coincides with the center of the two concentric arcs of different radii aforesaid. In the prior art constructions, the radius of the rotor has been such as to be substantially equal to the radius of the smaller of the aforesaid arcs of the bore, so that the rotor has a running fit with the smaller of the two arcs which defines a portion of the internal curve of the bore,

vanes, variously arranged as to position. and movement in the bore and extending diametrically there-across, serve as the means whereby fluid-is transported from one side of the rotor tothe other, such vanes, in their extended positions, spanning the space between the periphery of the rotor and the larger of the two concentric arcs aforesaid.

.It is a principal object of my invention to provide a pump structure of the character described,

but. modified as to certain particulars so as to" not only improve the functional characteristics of the pump, but to also materially lengthen the life of the pump by substantially reducing the wear to which the same is subjected.

Other objects of my inventionwill appear as the description proceeds.

To the accomplishment of the foregoing and related ends,v said invention then comprises the features hereinafter'fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways inwhich the principle of the invention may be employed.' In said annexed drawing:

Fig. 1 is a sectional view of one form oi'vane pump showing an embodiment of my invention:

and v Fig. 2 is a transverse sectional view ot the structureailiustrated in Fig. 1, taken on a plane substantially indicated by the line 2+2.

'pacity of the pump,

Iii times the n Referring now more speciilcally to the drawing and moree'speci'ally to. Fig; 1', it will be ob served that the pump comprises a housing generally indicated at I, having an inlet opening 2, and a dischargexopening'l'. Centrally of: the body I there is provided a cylindrical opening 4,.into which is-press-fltted a stator I; theouter periphery of which is cylindrical to conform to the:

cylindrical opening 4 receiving the same,

Rotatably supported in the housing 1,. and within the stator 5, is a rotor i carrying apmrality of diametrically arranged vanes 6a in a manner conventional in the art;

Theinner periphery orthe stator 5 is divided into four parts-an area generally indicated at 1 which is cylindrical; an area indicatedat 8 which is likewisecylindrical; andareasi and III which are a variation from a true arc, these being generally a limaconcurve or variations thereof,

aboutwhich thisinventionis not concerned.- The curves land I'll aresuch that when solid elemenrically arranged vanes are carried by the rotor, the opposite ends of each such vane will be at all times in substantialcontact with the curves 9 and It; The center of the rotoris indicated at H. This point II is also the center. of the oral; as well as the are 8', although the radius'oi the are 1 is substantially shorter than the" radius of the arc 8. I I Fig. 2 is a broken sectional view or Figs 1:, and similar reference characters have been applied thereto to denote like parts, and from the foregoing description, it is believed that the principal features of the pumpwill be readily understandable to those skilled in the art; g

The improvement about which this invention is concerned is the relative proportions oi the radius or the rotor with respect to the radius" of the smaller are 1. Heretoiore, pumpshavebeen constructed with the radius of the rotor substantially equal with the radius of" the are I so as to provide stunning fit between the: rotor and such. smaller curved surface In: accordance with my iriv'ention,v the radius of the smaller are! is always substantially greater than the radius of" the-rotor'oi' the puxnm providirig a substantial clearance between the rotor and-the stator in such area.- Oi course, the cawhich would, according: to lume between the the large: are 8' of the rotor,

the riorart, be roughly the v rotor and the" stator opposite I times the revolutions per minute is reduced by the amount: oi the space between: the rotor and her of revelutions' per: minute, oi

volume in the the smaller curve" I the rotor. This is not a serious handicap since it is'convenient. in providing a pump of given capacity, to slightly increase the radii of the curves 7 and 8 to compensate for this difference.

The clearance, or more accurately the space of substantial proportions between the rotor and the smaller are 1 has a number of advantages, certain of which may be enumerated as follows:

Most commercial materials adapted to be handled by pumps of this character, such as for example a fuel for internal combustion engines, occasionally contain small amounts of entrained foreign matter which have a tendency to-be car.-'

ried around by the rotor blades and "lodge in the space between the rotor and the smaller arc or curve of the stator. When a running fit is provided between the rotor and stator in this area, such foreign material destroys the running fit and impairs the function of the "pump in destroying this running fit, and even on oc-.

casion varies the capacity of the pump slightly.

Still another, and even more important function of this clearance between the rotor and stator,is to avoid certain difficulties experienced in the prior art pumps in their use of vanes with curved ends. From an inspection of Fi g. x1, it

advantages incidental to my improved construction will be apparent to those familiar with the art.

- I have not attempted to describe in detail those portions of the pump structure illustrated which are not a part of my invention. The general form of pump which has been illustratedfor the purpose of showing the application of one form of my invention will be recognized as corresponding in general to the pump illustrated and described in Curtis Patent No. 2,165,963 to which reference may be had for a more detailed description of. the arrangement and. mode of operation of the parts in general.

The present improvement is concerned not with the number of vanes employed in the pump,

-: nor the precise curve utilized for connecting the will be observed that upon counter-clockwise rotation of the rotor-,the rearedge of the vane has a tendency to ride on the expanding curve In, and the'forward-edge of the vane has a tendency.

to ride on the contracting curve 9. y

In order to reduce the rate of wear, mam" which is not completely-filled by the vane because of the relieved corners of the vane. This pocket is filled with the material being handledby the pump, terial, such same, due to an actual pinching and binding thereof in these small pockets, has had a tendency to volatilize and give rise to objectionable difiiculties in the handling of such material.

When a substantial distance or space ismaimtained between the stator and the rotor in the area of the small arc of the bore, and for my and when a relatively volatile mapurposes this space is always greater than the extent to which the ends of the blades are relieved in providing the curved ends on the blades, there is never any trapping of the fuel in small pockets which has heretofore led to the pinching and binding aforesaid.

A pump constructed in accordance with my invention is, therefore, much freer running than the pumps of the prior art; is less apt to deteriorate on account of wear. due to the inclusion of entrained foreign particles in the material being handled, by the pump; and "produces a smoother flow with a lesser tendency toward the setting up,v of pulsations on the discharge side than the similar pumps of the prior art. Other as gasoline, ,is thus handled, the

two concentric cylindrical surfaces of the bore body, since my invention is applicable in genera] to rotarypumps-having this general arrangement of working parts.

Other "modes of applying the principle of the inventionmay be employed,- change being made as regards the detailsdescribed provided the features stated in. anyof the, following claims.

or the equivalent of such be employed.

I therefore particularly point out and distinct 1y claim as my invention:

1. In a pump of the characterdescribed, the

combination of apump body having a bore, the normal cross-section of which is defined bytwo concentric arcs of unequal radii, with vane-extending and retracting curvesjoining adjacent ends of said arcs, a substantially cylindrical rotor mounted concentrically with said arcs, vanes slidablylcarried by said rotor and in engagement at all times atntheir opposite terminal portions with the inner periphery ofsaid bore,;-said bore en-.

gaging terminal portions of said vanes being arcuately relieved from substantially the center.

plane thereof to the opposite sidesthereof, said pump being characterized in that the radius-of. said rotor is substantially less than the radius of the smaller of said concentric arcsby an amount at least as great as'the radial extent by which-said vanes are relieved.

2. In-a pump of the character described, the combination of a pump body having a bore, the

normal cross-section of which is defined by two" concentric arcs of unequal radii, with vane extending and retracting curves Joining adjacent a mounted concentrically with said arcs, vanes slidably carried by said rotor and in engagement at'all times at their opposite terminal portions with the inner periphery of said bore, said bore engaging terminal portions of each of said vanes being so proportioned, with respect to the smaller chamber arc, that each of said vanes projects" at all times bevnnd thesurface of the rotor and no pocket is formed between the sides of the vane and the sides of its slot while said vane is in contact with and passing across said smaller arc, said pump being characterized in that the radius of said rotor is substantially less than the radius of the smaller of said concentric arcs.

JOSEPH B. BRENNAN.

ends of said arcs, a substantially cylindrical rotor 

